(a) Field of the Invention
The present invention relates to a novel and useful iron colloid-labeled antibody which is used for the histochemical detection of specific constituents of cells or tissues under a light microscope and an electron microscope in medical or biological experiments.
(b) Description of the Prior Art
As the labeled antibody for the histochemical detection of specific substances present in tissues or cells, and constituents of tissues or cells, there have been known and generally widely used the fluorescent antibody, the peroxidase-labeled antibody, the ferritin antibody, the gold colloid-labeled antibody and the like.
Of the histochemical detecting methods wherein these various labeled antibodies are used, the fluorescent antibody method was developed for ultraviolet microscopy, which can not be utilized for general light microscopy and electron microscopy and gives only indistinct images. The peroxidase-labeled antibody method (PAP method) is very excellent and widely used for light microscopy and electron microscopy now. However, the specimens post stained with osmic acid, uranium acetate, lead citrate or the like are liable to show unclear existence of the reaction products, because of diffuse appearance of the reaction products under an electron microscope. In respect to this point, the staining by the ferritin antibody method or the gold colloid-labeled antibody method provides very distinct electron microscopic images. However, these methods are difficult to expect distinct light microscopic images and have the disadvantage that the tissue permeability of the labeled antibody is remarkably poor because the labeled antibody is large in size.